<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>轮播图</title>
<link rel="icon" type="image/x-icon" href="picture/图标logo.ico">
<!-- <script type="text/javascript" src="demo.js"></script> -->
</head>
<style type="text/css">
	*{
		margin: 0;
		padding: 0;
	}
	ul{
		list-style: none;
	}
	a{
        text-decoration: none;
    }
	#container{
		position: relative;
		width: 500px;
		height: 260px;
		margin: 20px auto;
		overflow: hidden; /*溢出隐藏：只显示一张图片*/
	}
	#container .parent{
		position: absolute;
		width: 2500px; /*整个图片层长度：500*5=2500*/
		height: 260px;
	}
	
	#container .parent li{
		float: left;
		width: 500px;
		height: 100%;
	}
	#container .parent li img{
		width: 100%;
		height: 100%;
	}
	#container .btnLeft,
	#container .btnRight{
		width: 30px;
	    height: 30px;
	    background-color: #9E9E9E;
	    border-radius: 20%;
	    opacity: 80%;
	    position: absolute; /*包含块为图片显示层container*/
	    top: 0;
	    bottom: 0;
	    margin: auto;
	    font-size: 20px;
   	 	color: #f40;
   	 	text-align: center;
   	 	line-height: 30px;
	}
	#container .btnLeft{
	    left: 10px;
	}
	#container .btnRight{
		right: 10px;
	}
	#container .btnLeft:hover,
	#container .btnRight:hover{
		opacity: 90%;
		cursor: pointer;
	}
	/*蒙层*/
	#container .modal{
		width: 100%;
		height: 40px;
		background: rgba(0,0,0,.3);
		position: absolute;
		left: 0;
		bottom: 0;
		line-height: 40px;
		padding: 0 40px;
		box-sizing: border-box;
	}
	#container .modal .title{
		float: left;
		color: #fff;
		font-size: 12px;
	}
	#container .modal .dots{
		float: right;
		position: absolute;
		bottom: 10px;
		left: 340px;
	}
	#container .modal .dots li{
		width: 15px;
		height: 15px;
		border-radius: 50%;
		float: left;
		/*可以使用行块盒*/
		/*display: inline-block;*/
		margin: 0 5px;
		cursor: pointer;
	}
	.clearfix::after{
		content: "";
		display: block;
		clear: both;
	}
	.on{
		background-color: red;
	}
	.off{
		background-color: gray;
	}
</style>
<body>
<div id="container">
	<ul class="parent" style="left: 0;">
		<li><img src="image\4345114.jpg"></li>
		<li><img src="image\4345114.jpg"></li>
		<li><img src="image\4345114.jpg"></li>
		<li><img src="image\Liskam_65411813.jpg"></li>
		<li><img src="image\Liskam_65411813.jpg"></li>
	</ul>

	<div class="btnLeft">&lt;</div>
	<div class="btnRight">&gt;</div>
	<div class="modal">
		<div class="title">
			<h2>轮播图</h2>
		</div>
		<div class="dots">
			<ul class="clearfix">
				<li class="on"></li>
				<li class="off"></li>
				<li class="off"></li>
				<li class="off"></li>
				<li class="off"></li>
			</ul>
		</div>
	</div>
</div>
<script type="text/javascript">
	
var imgShow = document.getElementsByClassName('parent')[0],
	dotList = document.querySelectorAll('.dots >.clearfix > li');
var btnLeft = document.getElementsByClassName('btnLeft')[0],
    btnRight = document.getElementsByClassName('btnRight')[0];
var dotLen = dotList.length,
	index = 0; //轮播层的图片索引，0表示第一张

//圆点显示
function showRadius() {
	for(var i = 0; i < dotLen; i++) {
		if(dotList[i].className === "on"){
			dotList[i].className = "off";
		}
	}
	dotList[index].className = "on";
}

//向左移动
btnLeft.onclick = function() {
	index--;
    if(index < 0){  /*第1张向左时，变为第5张*/
        index = 4;
    }
    showRadius();
	var left;
	var imgLeft = imgShow.style.left;
	if(imgLeft === "0px") { /*当是第1张时，每张图片左移，移4张图，位置为-(4*500)*/
		left = -2000;
	}
	else{
		left = parseInt(imgLeft) + 500; /*由于left为负数，每左移一张加500*/
	}
	imgShow.style.left = left + "px";
}

//向右移动
btnRight.onclick = function() {
	index++;
    if(index > 4){  /*第5张向右时，变为第1张*/
        index = 0;
    }
    showRadius();
	var right;
	var imgLeft = imgShow.style.left;
	if(imgLeft === "-2000px") { /*当是第5张时，第1张的位置为0*/
		right = 0;
	}
	else{
		right = parseInt(imgLeft) - 500; /*由于left为负数，每右移一张减500*/
	}
	imgShow.style.left = right + "px";
}

// 自动轮播
var timer;
function autoPlay() {
	timer = setInterval(function() {
		var right;
		var imgLeft = imgShow.style.left;
		if(imgLeft === "-2000px") {
			right = 0;
		}
		else{
			right = parseInt(imgLeft) - 500;
		}
		imgShow.style.left = right + "px";
	} ,1000)
}
autoPlay();

for(var i = 0; i < dotLen; i++) {
    /*利用闭包传递索引*/
    (function(i) {
        dotList[i].onclick = function() {
	        var dis = index - i; //当前位置和点击的距离
	        imgShow.style.left = (parseInt(imgShow.style.left) + dis * 500) + "px";
	        index = i; //显示当前位置的圆点
	        showRadius();
    	}
    })(i);
}

</script>

</body>
</html>
